This 1965 circuit uses a Philips 4068 tube to measure extremely small charges. The circuit has as indicator a micro ammeter and the transistors are of the time.
This circuit is from an English publication from 1973, but can be easily assembled today. 2N718 can...
A four-bit analog-to-digital converter [A/ D or ADC] can be built using one 4066. An 8-bit...
In the figure we have an application of an oscillator 4013 as voltage multiplier. It consists of a...